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🔍 What is DAST?
Dynamic Application Security Testing (DAST) is a black-box security testing method that analyses running applications by simulating real-world attacks. Unlike SAST, DAST doesn’t need access to source code — it tests the app from the outside in, just like an attacker would.
DAST is crucial for detecting runtime vulnerabilities, especially in web applications and APIs.
⚙️ How DAST Works
DAST tools interact with a live instance of your application, sending crafted HTTP requests and observing responses to detect:
- SQL injection
- Cross-site scripting (XSS)
- Authentication & session flaws
- Insecure redirects
- Server misconfigurations
- API abuse or information disclosure
📦 DAST in the DevSecOps Pipeline
| Phase | Action |
|---|---|
| Post-deployment | DAST runs against a test or staging environment. |
| Automated Security Tests | Can be integrated into CI/CD pipelines for continuous testing. |
| API Coverage | Modern DAST tools support OpenAPI/Swagger-based scanning. |
🧪 Popular DAST Tools
| Tool | Type | Notes |
|---|---|---|
| OWASP ZAP | Open-source | Actively maintained, good for automated and manual testing. |
| Burp Suite Pro | Commercial | Widely used by security professionals. |
| Acunetix | Commercial | Focuses on web app and API scanning. |
| Netsparker | Commercial | DAST with automation and reporting features. |
| Nikto | Open-source | Basic web server scanning tool. |
🧠 DAST vs SAST
| Feature | DAST | SAST |
|---|---|---|
| Type | Dynamic (runtime) | Static (code-level) |
| Code Access | Not required | Required |
| Best At | Runtime issues, misconfig, logic flaws | Coding flaws, bad patterns |
| When | After deployment | During development |
✅ Benefits of DAST
- Tests applications in real-world conditions
- Detects runtime vulnerabilities missed by code reviews
- Works with any language or platform
- Ideal for testing third-party apps or closed-source software
- Enhances overall app resilience and robustness
⚠️ DAST Challenges
- Needs a running environment (test/staging or live)
- May struggle with complex workflows or JavaScript-heavy UIs
- Can generate false negatives without good coverage
- Slower than SAST when integrated into fast CI/CD cycles
🔐 Advanced Use Cases
- Authenticated Scanning: Supply login credentials to test deeper parts of the app
- API Testing: Upload Swagger/OpenAPI definitions for full endpoint coverage
- Regression Testing: Re-scan known issues automatically to validate fixes